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1answer
42 views

Find distribution of underlying feature

Let's say I have a dataset with values for the variable $W$. The distribution of $W$ doesn't follow any obvious known distribution. I have a model that gives $W$ as a functions of $E$ and $K, W = ...
0
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2answers
30 views

Fitting a GEV distribution - non-negative only

I am fitting a GEV distribution to some rainfall data, but the software I am using (Matlab and Easyfit) are giving a distribution which includes negative numbers (i.e. negative rainfall). Is there a ...
1
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0answers
10 views

estimating model fit parameters using simulations

I'm trying to fit 2D ellipticals gaussians to an image (with correlated background noise) using prewritten fitting software. I'd like to know about the uncertainty in the fit parameters with this ...
0
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0answers
12 views

loglikelihood for HMM with continuous emissions

I have a HMM and that has continuous valued emissions. I model the emissions using Weibull distributions. After I run the HMM I get the states, transition probabilities, priors and shape,scale ...
0
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0answers
4 views

Using matlab to fit data with negative binomial distribution under given p? [migrated]

How to use matlab to fit data with negative binomial distribution under given p?
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0answers
7 views

Fit vertices to minimize Error when linearly interpolating

For a curve like the one below: Given that we have a certain amount of vertices for approximation, say 5. How to find appropriate x values to place the vetices on ...
1
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0answers
26 views

Fitting multiple normal distributions to sample data

I have a data set of (time, action)-tuples. Actions are typically performed at approximately the same times every day, and depending on what the action is it may be done multiple times per day. If I ...
1
vote
1answer
79 views

Fitted Beta distribution always holds water. Can I force it not to?

I am trying to fit a beta distribution to election forecast data. The ultimate purpose is determining with what probability the election will be decided by one vote (more on this here). My data is as ...
0
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0answers
17 views

geeglm not recognizing clusters

I am fitting a geeglm model and it is not recognizing the clustering. my model is ...
1
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0answers
57 views

How to determine if GLM quadratic term should be set up orthogonal or non-orthogonal

I am setting up a GLM in R where I have only one predictor variable and its quadratic form. I understand that in R I have 2 options. ...
0
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0answers
28 views

Do we fit this time series data with time series model or spline?

Basically, I have the following data with the number of item A on the vertical axis and the time on the horizontal axis (from 1st hour to the 24th hour). I don't have much experience in fitting a ...
1
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0answers
37 views

Align two datasets in Python

I want to develop some python code to align datasets obtained by different instruments recording the same event. As an example, say I have two sets of measurements: ...
0
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0answers
39 views

How do I verify whether a population distribution is a power-law? [duplicate]

given a population of discrete values (not a sample), is there any way to check whether the distribution is a power-law, and with what parameters? Of course I can just plot the distribution and see ...
0
votes
0answers
24 views

Least-squares fitting with only optimum features, after Lasso - valid?

Using Lasso reduces the coefficients of features of a model, reducing some to zero, and thereby performing feature selection. The number of features depends on the value of $\alpha$ aka $\lambda$. In ...
1
vote
0answers
18 views

Least Squares Regression - Error [duplicate]

In standard least squares regression, we find constants $\beta_1$ and $\beta_2$ such that the square of the average error, $\epsilon = y_i - (\beta_1 + \beta_2x_i)$, is minimized, and so the 'line of ...
0
votes
0answers
39 views

How to run an nls model in R to generate output parameters for independent categories?

I would like to get help on the following code: library(nlme) funct1 <- function(scale1,a){ exp((scale1 - 2)/a) } ...
0
votes
1answer
36 views

How to calculate the probability of a datapoint fitting in a known distribution

I have a set of samples, each with a concentration for element A which is shown on a log scale on X-axis on the histogram below. The number of samples with the same concentration is shown on Y-axis. ...
0
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0answers
13 views

How to fit raw signal

I think this is simple, but somehow it's not working. I'm trying to fit my raw data so that basically I end up with beautiful 1 peak. I tried butterworth filtering, Gaussian fitting, a combination of ...
0
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0answers
22 views

How should I fit this data?

I have a dataset: ...
1
vote
2answers
101 views

Power law fitting of data with uncertainties

I need to fit data points on a power law and each one of these carries an uncertainty. I've been using Python, more precisely scipy.optimize.curve_fit to get the job done but I don't know how to ...
0
votes
1answer
24 views

Is there a statistical differing interpretation between match and fit?

I've seen the terms matching/match and fitting/fit used almost interchangeably when discussing models goodness of fit, observed vs simulated data matching, etc. Is there a difference in ...
0
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0answers
15 views

Limiting the range of possible values for distribution fitting with GAMLSS in R

I'm trying to fit ST5 distribution for reaction times with GAMLSS. Sometimes mu parameter of the distribution is negative, which is implausible. Is it possible to limit the range of parameter values ...
0
votes
1answer
40 views

Regressing, analysing data with points rather than polynomial?

I am looking into making a regression of a bunch of data that is contained on some range of real numbers. In my case, x is between 0 and 1 and y is between 0 and 10. If I have 150 data points on this ...
2
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0answers
27 views

Fitting a straight line to components of complex numbers

I have a strange problem that I'm not sure how to solve: I have complex data points in a time series. The amplitude of these complex numbers in the time series forms a straight line, which I have fit ...
2
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0answers
19 views

Polynomial Data Fitting for Two Unknown Equation

I have a kind of data and want to find the equation(poly coeff) of given data. For example equation for given sample data is simple a^2*b+10 ...
-3
votes
1answer
47 views

code for ordered probit model

I have a data set with 7 predictor variables and one dependent variable. The dependent variable has 4 categories so it's not binomial. I need to fit a probit model. I need codes for probit model in ...
1
vote
1answer
24 views

Comparing polynomials

I've got a bunch of data on pop singers' performance on the Hot 100 charts over time, and I'm trying to compare the early part of different artists' careers. For example, I might look compare Miley ...
3
votes
1answer
271 views

Determining probability distribution for datasets with missing values

As a part of my exploratory data analysis (EDA) prior to further analysis, I'm trying to determine a probability distribution of my pilot dataset's variables. A particular feature of this dataset is a ...
7
votes
2answers
594 views

What to do when CFA fit for multi-item scale is bad?

I am not sure how to proceed with this CFA im doing in lavaan. I have a sample of 172 participants (I know that’s not much for a CFA) and 28 items with 7-point Likert scales that should load on seven ...
0
votes
1answer
194 views

Fit measures for GMM Arellano-Bond estimator in R

A colleague and I have been working with difference GMM, i.e. the Arellano-Bond estimator, in R. Our option has been to use the pgmm command from the plm package. However, now I am struggling to test ...
1
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0answers
54 views

How can I use Akaike's Information Criterion to compare two models of multi-peaked emission spectra?

I have several photoluminescence emission spectra that I am trying to fit curves to. The spectra each have a slight baseline and four peaks. The independent variable $x_i$ is wavelength (converted to ...
0
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0answers
74 views

How to validate goodness of fit and forecasting quality of a model?

I am working on big data sets, which represent electricity consumption on power substation throughout the year. I have data every 10 minutes and multiple (and long) seasonalities. I have a daily, ...
1
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0answers
25 views

Retreiving Integrated Fitted Data from Stationary Fitted Data

Note that this is a simplified example: I have some time series that I made stationary by differencing twice. Then I ran arima on it, and set d = 0 to prevent ...
0
votes
0answers
13 views

Artificial distribution to best match an actual one

There's a problem I am struggling to solve, if anything because I can't find the right angle from which to attack it. It's basically a fitting problem, and possibly a topological one, although I'm not ...
4
votes
1answer
115 views

Model with non-linear transformation

I don't understand this concept well and need help. I was choosing whether to use a linear model or apply a non-linear transformation in my model formula. To do a diagnostic, I quickly plotted my ...
1
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3answers
113 views

How to make IPF code faster and more concise in R

Iterative proportional fitting is a way of adjusting 'internal cells' in a multidimensional matrix to optimise fit. It is also known as 'raking' and can be seen as a subset of 'entropy maximisation'. ...
0
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0answers
34 views

Applying Delta Method to generate prediction bands for custom distributions step by step

I think that this is an interesting issue for all those who whan to not only adjust one prediction function, but also to obtain the prediction bands to asses the graphical or tabular error I'm trying ...
0
votes
1answer
106 views

Errors when fitting a SARIMAX model in R

Currently working on big data sets, I would like to fit a SARIMAX model to it in order to forecast future values. Here are my questions : Q1. As a matter of information, does anybody know how does R ...
2
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0answers
42 views

How to approximate error on Chi-Squared Fit when bin counts are zero

I am using a galaxy image simulator that provides a 2D histogram that has the number of photons per pixel (bin) $N$. I am currently using a least-squares residual: $\sum_{bin}(f_{data}-f_{model})^2$ ...
1
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0answers
38 views

Estimating a distribution from a dataset with multiple parameters

How would you go about solving the following problem? You're an insurance company who writes workers compensation policies. You want to build a probability distribution for the number of annual ...
1
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0answers
44 views

Estimating Parameters of truncated generalized pareto distribution by probability weighted moments

Is it possible to estimate parameters for a truncated Generalized Pareto Distribution (Wikipedia Article) by probability weighted moments? If not, why is that so? I am aware that it would be possible ...
1
vote
1answer
131 views

Logistic Regression - Model Does not Fit

My name is Abhi and I am fairly new to statistics. I found some sample exercises online & I am trying to solve them to get a better understanding of model development. Problem Statement Assume ...
1
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3answers
144 views

Issues with fitting distribution to heavy-tailed data

I am currently trying to fit distributions to some heavy tailed data-set (see the data set below) and have a hard time producing good results: ...
0
votes
1answer
83 views

Estimating a distribution based on three percentiles and a mean

I have a set of percentiles the 10-th, 50-th and 90-th. Furthermore I have the mean value. I am trying to reconstruct the underlying distribution. The question is similar to Estimating a ...
2
votes
1answer
54 views

Finding analytic form for distributions using linear regression, need ideas

I'm trying to find an analytical form to describe these probability density functions: I'm pretty new to all of this, but think I should use some linear combination of basis functions (so I can then ...
4
votes
1answer
188 views

“Better” goodness-of-fit tests than chi squared for histogram modeling?

I work on data from a mass spectrometer that produces billions upon billions of count histograms, and I need a good way to test whether these histograms are consistent with one or several model ...
0
votes
1answer
51 views

Regression model for $f(x_1, x_2) = a + b x_1\log x_2$

Which regression algorithm do I need to use to fit the coefficients of $f(x_1, x_2) = a + b x_1\log x_2$? Will linear regression with an independent variable $x_1 \log x_2$ work?
0
votes
0answers
32 views

How to find out some particular distribution given the grouped data and a polynomial fitted to the data

I have to analyse a set of grouped data.The data is divided into groups by some categories for example: BP(<=60), BP((60,80]); Pulse(<75), Pulse((75,90]) & Pulse(>90) etc having many more ...
0
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0answers
152 views

Fitting for a Poisson-Gaussian Mixture Distribution

First of all, I am rather new to statistics, so go easy on me. I am aware that the negative binomial distribution can be thought to arise as a result of letting the $\lambda$ parameter in a Poisson ...
0
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0answers
19 views

How to incorporate a noise model into a probabilistic model?

Let's say have a probabilistic model $m$ which I fit to data using maximum likelihood. Now, I would like to add a noise model $n$ which I can also fit independently using maximum likelihood. So I am ...